The trans-Saharan trade was very similar to some major trends in Africa during this period. It was very much connected to the growth of kingdoms and the growing cultural mixing that were important trends in Africa during this very long period.
During the period in which the trans-Saharan trade existed, many African trading kingdoms came into existence. The importance of trade, then, is one of the most important trends that went on during this tiem. In addition to (and in many ways because of) this trade, there was the trend towards more cultural mixing. Perhaps the most obvious examples of this were the coming of Islam and then, later, the influence of European contact.
During the long period from 600 to 1750 CE, trading kingdoms arose and became important in Africa. At the same time, cultures came to influence one another. The trans-Saharan trade was related to both of these trends.